3.1l vint question

[alfi1]

hi everybody

i'm new here and i want to ask 2 questions

 

1- where is the engine coolant drain plug (not the radiator one)of my lumina 91 3.1l vin t?

 

2-what's the difference between open and close loop when you talking about ecm? theory of operation!!

 

thank to answer

 

[Whiskey River]

Well, to answer your first question, I would have to look in my service manual but as for the second question, I can answer.

 

Open Loop is when the ECM is basically not using the O2 sensor to make fuel adjustments. During Open Loop operation the ECM is using it's fuel and spark tables, without correction. The only time your vehicle should be in open loop is when first started up, when the Coolant temp sensor reads below 125 degrees or during extended idle periods. Some have reported that the ECM will go into Open loop during hard acceleration but I have not personally seen this so I can not verify it.

 

Closed Loop is when the ECM uses the O2 sensor to make fuel delivery adjustments. If the O2 sensor indicates a rich condition, it shortens the Injector Pulse Width, the opposite for a lean condition. When in closed loop the ECM is using the same fuel and spark tables as in open loop but now there are corrections being made to keep the engine running at a A/F ratio of 14.7.

 

If you have any other questions or if this doesn't make sense, let me know and I'll try to explain a little better.

[-L82-Loser]

When in closed loop the ECM is using the same fuel and spark tables as in open loop but now there are corrections being made to keep the engine running at a A/F ratio of 14.7.

actually, thats waaaaaay lean. 14.7:1 is the stoichiometrically ideal mixture ratio. however, this makes EGT's pretty high, and also causes higher NOx emissions. usually, the ratios are down in the 12-13:1 range, which means that not all the fuel is being consumed. the cat burns it off at a lower temp, which is more eco-friendly. plus, your engine would shit a brick from running so hot.

[Whiskey River]

Loser]

When in closed loop the ECM is using the same fuel and spark tables as in open loop but now there are corrections being made to keep the engine running at a A/F ratio of 14.7.

actually, thats waaaaaay lean. 14.7:1 is the stoichiometrically ideal mixture ratio. however, this makes EGT's pretty high, and also causes higher NOx emissions. usually, the ratios are down in the 12-13:1 range, which means that not all the fuel is being consumed. the cat burns it off at a lower temp, which is more eco-friendly. plus, your engine would shit a brick from running so hot.

 

Well, my ECM attempts to keep the A/F at 14.7:1. Back in the 80s, GM used to have "Highway Mode" on the cars that raised the A/F to almost 17:1. Once the EPA caught on they stopped it but I'll bet if you hook up any car to a monitor, once it is warmed up to normal operating temp, the ECM will attempt to keep the A/F at 14.7:1.

[alfi1]

Well, to answer your first question, I would have to look in my service manual but as for the second question, I can answer.

 

Open Loop is when the ECM is basically not using the O2 sensor to make fuel adjustments. During Open Loop operation the ECM is using it's fuel and spark tables, without correction. The only time your vehicle should be in open loop is when first started up, when the Coolant temp sensor reads below 125 degrees or during extended idle periods. Some have reported that the ECM will go into Open loop during hard acceleration but I have not personally seen this so I can not verify it.

 

Closed Loop is when the ECM uses the O2 sensor to make fuel delivery adjustments. If the O2 sensor indicates a rich condition, it shortens the Injector Pulse Width, the opposite for a lean condition. When in closed loop the ECM is using the same fuel and spark tables as in open loop but now there are corrections being made to keep the engine running at a A/F ratio of 14.7.

 

If you have any other questions or if this doesn't make sense, let me know and I'll try to explain a little better.

 

 

 

thank for the answer,now i understand.

 

for the engine coolant drain plug ,i appreciate if you can look in your service manuel ,because in the haynes repair book and chilton book they don't specifie the location ,when i drain my coolant ,no problem to purge the radiator and hose but the engine block remain full..

[OldsmoBeast]

Well, to answer your first question, I would have to look in my service manual but as for the second question, I can answer.

 

Open Loop is when the ECM is basically not using the O2 sensor to make fuel adjustments. During Open Loop operation the ECM is using it's fuel and spark tables, without correction. The only time your vehicle should be in open loop is when first started up, when the Coolant temp sensor reads below 125 degrees or during extended idle periods. Some have reported that the ECM will go into Open loop during hard acceleration but I have not personally seen this so I can not verify it.

 

Closed Loop is when the ECM uses the O2 sensor to make fuel delivery adjustments. If the O2 sensor indicates a rich condition, it shortens the Injector Pulse Width, the opposite for a lean condition. When in closed loop the ECM is using the same fuel and spark tables as in open loop but now there are corrections being made to keep the engine running at a A/F ratio of 14.7.

 

If you have any other questions or if this doesn't make sense, let me know and I'll try to explain a little better.

 

 

 

thank for the answer,now i understand.

 

for the engine coolant drain plug ,i appreciate if you can look in your service manuel ,because in the haynes repair book and chilton book they don't specifie the location ,when i drain my coolant ,no problem to purge the radiator and hose but the engine block remain full..

 

 

are you sure? I think the coolant drains out of the radiator. I didn't know of any other plugs. I know that haynes doesn't have a location for one in their manual but that's probably because there isn't one?

[Whiskey River]

There is a drain plug for the block, but since I can really only check these at work I didn't bring my service manual with me. Once I get home tonight I'll look it up and try to logon.

[OldsmoBeast]

so ru sayin that if i drained out my coolant from the radiator and flushed it out with the hose and stuff, there's still old coolant in there??? Cuz I had old ethelyne glycol (green) in there at first and i put in Dex-Cool (Orange)....so does this mean that my dex-cool is useless now?

[Slade901]

Drain as much green coolant from your cooling system. The ratio of the orange and green coolant must be kept low to minimize the effects on freeze point.

 

BTW, I just replaced my coolant. I got me a coolant flush as well.

 

First, I drained the coolant from radiator drain plug. Filled it up with water and run my car with heater blower on high for 10-15 minutes. Let it cool down for a few minutes and then drain the coolant from the radiator.

 

Filled the radiator with the coolant flush and mixed with water. Drive the car around for 1-2 hours and then let it cool down and then drain the coolant.

 

Filled it up with water and run my car with heater blower on high for 10-15 minutes. Let it cool down for a few minutes and then drain the coolant from the radiator.

 

Filled it up again with water and run my car with heater blower on high for 10-15 minutes. Let it cool down for a few minutes and then drain the coolant from the radiator.

 

5Filled it this time with the orange coolant. I made it like 90%/10% mix because there is still water in the engine.

[Whiskey River]

Ok, here is what my service manual has on the block drain plugs.

 

3.1L - The front engine block drain is located between the starter and engine oil filter. The rear engine block drain is located by the engine crank sensor

 

3.4L - Rear block drain is by the engine crank sensor. The front drain connects to the engine oil cooler. Disconnect the left hose and that will drain the front of the block.

[alfi1]

i check that

 

thank a lot whiskey river

 

bye

[mdelorie]

On the whole coolant / dex-cool etc. topic:

 

I thought the two systems were absolutely NOT interchangable. but after reading this, does that mean that I can drain all my glycol and fill it with dex-cool? why might I want to do this?

[Slade901]

On the whole coolant / dex-cool etc. topic:

 

I thought the two systems were absolutely NOT interchangable. but after reading this, does that mean that I can drain all my glycol and fill it with dex-cool? why might I want to do this?

 

yep, you can drain green coolant as much as you can and fill it with that orange coolant.

 

Dex-Cool has better anti-corrosion and lasts 5 years but I replace my coolant anyway every 2 years either green or orange coolant.

[brian89gp]

Closed loop tries to maintain a 14.7:1 ratio, always. 12 or 13:1 is what you see during acceleration.

 

Open loop happens on warmup and in PE (hard acceleration, >60% throttle). The PE AFR is usually in the 13-11 range.